Improvement of dynamic notch toughness for the Zr56Co28Al16 bulk metallic glass by local pre-deformation

Mode I dynamic three-point bending fracture tests are conducted on both as-cast and local pre-deformed Zr56Co28Al16 bulk metallic glass specimens. Similar to quasi-static cases, the notch toughness of the pre-compressed specimens is improved compared with that of as-cast ones upon dynamic loadings, which is mainly attributed to the fact that the pre-compression can produce numerous shear bands, especially for main shear band, guiding and deflecting the cracks. In addition, the crack patterns and fractography are analyzed to evaluate the influence of local pre-existing shear bands on the dynamic fracture toughness.